Enhanced stability of gold clusters supported on hydroxylated MgO(001) surfaces.
نویسندگان
چکیده
The influence of surface hydroxylation on nucleation and sintering of gold nanoparticles was studied by comparison of Au deposition and thermal sintering on ideally terminated MgO(001) and hydroxylated MgO thin films, respectively. A combination of different spectroscopic techniques (TDS, XPS, IRAS) allows to establish a correlation between the degree of surface hydroxylation and the stability of gold atoms and clusters. Hydroxyl groups destabilize gold atoms on the MgO surface at 90 K; however, they enhance the stability of small gold clusters toward sintering at higher temperature.
منابع مشابه
Characterization of metal clusters (Pd and Au) supported on various metal oxide surfaces (MgO and TiO2)
Au clusters supported on the TiO2~001!/Mo~100! surface and Pd clusters supported on the MgO~100!/Mo~100! surface have been studied using temperature programmed desorption, ion scattering spectroscopy, scanning tunneling microscopy, and scanning tunneling spectroscopy. Three dimensional growth has been observed at 300 K for both cases. The adsorption energy of Au on the TiO2~001! surface has bee...
متن کاملFirst Principles Calculations of Supported Catalysts: CO Oxidation on MgO Supported Gold Nanoparticles
Introduction Bulk gold is a chemically inert metal, and had previously been disregarded as a candidate for catalytic applications [1]. Haruta’s pioneering work [2] showed exceptional reactivity on gold nanoparticles of 2-5 nm in diameter. Among reactions, the low temperature CO oxidation [3] on Au has created a strong interest. Model catalyst samples, which consist of planar metal oxide surface...
متن کاملCharging effects on bonding and catalyzed oxidation of CO on Au8 clusters on MgO.
Gold octamers (Au8) bound to oxygen-vacancy F-center defects on Mg(001) are the smallest clusters to catalyze the low-temperature oxidation of CO to CO2, whereas clusters deposited on close-to-perfect magnesia surfaces remain chemically inert. Charging of the supported clusters plays a key role in promoting their chemical activity. Infrared measurements of the stretch vibration of CO adsorbed o...
متن کاملBonding trends and dimensionality crossover of gold nanoclusters on metal-supported MgO thin films.
Bonding of gold clusters, , 16, and 20, on MgO(100) and on thin MgO films supported on Mo(100) is investigated using first-principles density-functional theory. Enhanced adhesive bonding is found for clusters deposited on metal-supported MgO films of thickness up to about 1 nm, or 4 to 5 MgO layers, originating from electrostatic interaction between the underlying metal and metal-induced excess...
متن کاملControl and manipulation of gold nanocatalysis: effects of metal oxide support thickness and composition.
Control and tunability of the catalytic oxidation of CO by gold clusters deposited on MgO surfaces grown on molybdenum, Mo(100), to various thicknesses are explored through temperature-programmed reaction measurements on mass-selected 20-atom gold clusters and via first-principles density functional theory calculations. Au(20) was chosen because in the gas phase it is characterized as an extrao...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of the American Chemical Society
دوره 132 12 شماره
صفحات -
تاریخ انتشار 2010